Nucleic acids are the basic polymers for the construction of life. They are gigantic chains of molecules (monomers) called nucleotides, linked together by covalent bonds (phosphodiester), where all the genetic information of a living organism resides.
The nucleic acid control and direct the synthesis of all proteins that make up a living being as well as its specificity and role in each of the vital processes. In addition, they are key in reproduction, allowing the formation of new chains that will constitute an entirely new individual.
The name of the nucleic acids comes from its location in the nucleus of the cells, from where they were extracted for the first time in 1869 by Johann Friedrich Meischer.
There are two different types of nucleic acid in all living beings:
- The Deoxyribonucleic Acid (DNA).
- The Ribonucleic acid (RNA).
They are structurally different in that the DNA possesses the deoxyribose sugar, while the ribose RNA, and its constitutive nitrogenous bases also differ: the DNA possesses adenine, guanine, cytosine and thymine, while the RNA substitutes the latter for uracil. And they fulfill, logically, different functions in the processes of biological synthesis.
Examples of nucleic acids
Deoxyribonucleic acid (DNA) . Structured in two chains of nucleotides joined together by hydrogen bonds, it can appear linearly (in eukaryotic cells) or circular (in prokaryotes and in mitochondria and eukaryotic chloroplasts). In some viruses there may be a single-stranded DNA. In the DNA is all the generic information necessary for the cellular functioning of the individual.
Ribonucleic acid (RNA) . Unlike DNA, it is single-stranded (except in specific cases) and its structures are usually shorter. If the DNA contains the genetic information (the pattern), the RNA is the executor of it in various areas. We can list four types of RNA:
- Messenger RNA . Synthesized in the cell nucleus, its function is to take the genetic information of the DNA to the cellular ribosomes, to print the amino acid synthesis of the protein chains. Once that is done, it is destroyed.
- RNA transfer . Small single chain molecules, whose role is to drive the amino acids from the cytoplasm to the ribosomes, following the sequence transmitted by the messenger RNA and thus conforming the proteins to be synthesized.
- Ribosomal RNA . It is the most abundant of the three (80% of the total), is part of the cellular ribosomes where the transcription of the mold is made and the new proteins are manufactured.
There are, in addition, other nucleic acids synthesized in the laboratory, that is, not present in any form of nature, and that are analogous to DNA and RNA:
- Nucleic Acid Peptide . Constructed from the replacement of the phosphate-ribose bridge (in RNA) or phosphate-deoxyribose (in DNA), with classical peptide bonds (with glycine or aminoethylglycine).
- Blocked Nucleic Acid (Morpholino) . Using a ring of morpholino (C 4 H 9 NO) instead of sugars, this nucleic acid could be produced, with which it has been possible to intervene in the replication of messenger RNA in certain conditions and organisms, allowing the development of genetic and pharmaceutical treatments. (antibacterial).
- Glycolic Nucleic Acid . Formed from the substitution of sugars for glycol, it is able to bind very naturally to natural DNA and RNA, being a simplified form of nucleic acid. For that reason it is speculated that it is the evolutionary precursor of the current ones.
- Phosotic Nucleic Acid . Instead of the ordinary DNA and DNA pentoses, it uses a threose. Given its ability to bind to RNA, it is estimated that it could have been its evolutionary precursor.
- Quimeroplasts . Used in gene therapy, they are nucleic acids of hybrid nature (RNA and DNA) used in strategies of correction and genetic substitution.